Chromatic ranging method and apparatus for reading optically readable information over a substantial range of distances

• US 5,468,950 A
• Filed: 07/28/1994
• Issued: 11/21/1995
• Est. Priority Date: 05/11/1992
• Status: Expired due to Term

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Norand Corporation (Baker Hughes Company)
• Inventors: Hanson, George E.
• Primary Examiner(s): PITTS, HAROLD I
• Application Number:
  US08/281,884
• Time in Patent Office: 481 Days
• Field of Search: 235/472, 235/462, 235/465, 235/469, 250/226
• US Class Current: 235/454
• CPC Class Codes: B60R 11/02 for radio sets, television sets, telephones, or the like; Arrangement of controls thereof
• CPC Class Codes: B60R 11/0241 for telephones
• CPC Class Codes: G06F 1/1626 with a single-body enclosure integrating a flat display, e.g. Personal Digital Assistants [PDAs]
• CPC Class Codes: G06F 1/1632 External expansion units, e.g. docking stations
• CPC Class Codes: G06F 1/28 Supervision thereof, e.g. detecting power-supply failure by out of limits supervision
• CPC Class Codes: G06K 17/0022 arrangements or provisious for transferring data to distant stations, e.g. from a sensing device "transfer between computer elements G06F13/00 "; data-transmission H04L
• CPC Class Codes: G06K 7/10574 Multiple sources
• CPC Class Codes: G06K 7/10584 Source control
• CPC Class Codes: G06K 7/10702 Particularities of propagating elements, e.g. lenses, mirrors G06K7/10831 takes precedence
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10811 Focalisation
• CPC Class Codes: G06K 7/10841 Particularities of the light-sensitive elements semiconductor devices H01L
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners
• CPC Class Codes: G06K 7/12 using a selected wavelength, e.g. to sense red marks and ignore blue marks
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles
• CPC Class Codes: H04B 2001/3894 Waterproofing of transmission device
• CPC Class Codes: H04W 4/18 Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals

Abstract

An improved method and apparatus for reading optical information over a substantial range of distances provides an optical string, disposed in a housing, for refracting images of optical information of varying wavelengths to different focal points along a longitudinal axis at a predetermined reading position. Adjacent the housing, and directed along the longitudinal axis of a housing opening and the optical string, is an illumination source for illuminating optical information with light. Also included is a reading sensor having a light receiving plane disposed at a predetermined reading position behind the optical string for converting an image of optical information into an electrical signal. A control system is also provided for determining and decoding the reflected light image formed by that wavelength of light received from the illumination source which produces the best focus on the light receiving plane of the reading sensor. Finally, an apparatus is also provided for producing a digital information set corresponding to the image of optical information focused by the optical string onto the receiving plane of the reading sensor.

Claims

1. A method of focusing an image of optical information over a substantial range of distances, comprising:

(a) sequentially reflecting light of varying wavelengths from optically readable information such that sequentially different wavelength images of said optically readable information are produced;

(b) refracting each sequentially different wavelength image of optically readable information produced by said varying wavelengths of light such that refracted light images are incident on the light receiving plane of a photosensitive array;

(c) producing a digital information set corresponding to each of said refracted light images of said optically readable information; and

(d) decoding said digital information set corresponding to said refracted light image having the sharpest focus.

2. An apparatus for focusing an image of optical information over a substantial range of distances, comprising:

(a) a housing having an opening for facing optical information;

(b) optical means, disposed in said housing, for refracting images of optical information of varying wavelengths to different focal points along a longitudinal axis at a predetermined reading position;

(c) reading sensor means, disposed at said predetermined reading position and having a light receiving plane, for converting an image of optical information into an electrical signal;

(d) control means for determining and decoding the reflected light image formed by that wavelength of light from said optical means which produces the best focus; and

(e) means for producing a digital information set corresponding to the image of said optical information.

3. A method of focusing an image of optical information over a substantial range of distances, comprising:

(a) splitting the reflected light image of optically readable information into component wavelength refracted images;

(b) producing a digital information set corresponding to each of said refracted light images of said optically readable information; and

(c) decoding said digital information set corresponding to said refracted light image having the sharpest focus.